The Advantage of a Cold Start on your Diesel

Article 3 of a 3 part series.

Temperatures below the freezing mark make your diesel harder to start.  That’s not a surprise however it is much more complex than you might think.  Consider this…the ambient air temperature and air pressure decrease your battery power and increase oil viscosity which can lead to increased engine friction.   This also impacts starter speed and compression ratio.  Combine these circumstances with the efficiency of the injectors, your fuel cetane and fuel fluidity which leads to a higher torque demand on the engine and a lower starting speed.  This complex series of events may or may not lead to a successful ignition and start.

One of the advantages of cold weather is that it reveals weaknesses that your engine was experiencing during warm weather but the symptoms weren’t dramatic enough to notice.  Most often, those symptoms are lower MPG that directly impacted your wallet.

For example, when the temperature is above 40 degrees your diesel’s engine oil is thin and runny.  If the injectors are not firing at maximum efficiency due to stiction (sticky, gummy residue left by burnt oil) your engine may still start without hesitation even though stiction is negatively impacting MPG.

The first time it gets below 40 degrees the engine oil starts to thicken and gets gummy.  That injector with barely noticeable stiction now is experiencing increased hesitation.  The diesel becomes hard to start.  It shakes.  It rocks.  It doesn’t want to settle down. You pull out and there is no throttle response. No giddyup.  It takes 15 minutes to get up to 50 MPH.

The good news is that you very likely just diagnosed a stiction problem which can be quickly and easily resolved with one treatment of Hot Shot’s Secret Stiction Eliminator.  Add it with your oil change and give it 500 miles to work through the oil system.  Your smoke output may increase slightly during this period as the stiction is being removed and expelled via the exhaust.

Chris Gabrelcik is certified with STLE as a CLS and OMA.  He personally developed and tested a product designed to remove stiction called Hot Shot’s Secret Stiction Eliminator.

What is “Stiction?”

In recent years, the term “stiction” has joined the conversation between diesel mechanics and drivers. But what is stiction, exactly?

This simple demonstration will help you visualize stiction.  Pour a small amount of water on a counter-top.  Now slide a paper towel over the spill.  Feel the difference in the amount of drag after the towel absorbs the water.  That drag is stiction.

Imagine the inside your diesel’s injector.  A thimble full of engine oil has the high pressure job of driving the intensifier piston under extreme heat.  Over time, that small amount of engine oil breaks down and leaves a gummy residue on the internal parts.  As those parts move, they experience a drag (like the wet paper towel).  The sticky, gummy residue of burnt oil on moving engine parts causes a dragging friction.  We call that stiction.

Drivers sometimes choose to use lubricants to resolve stiction.  This creates a temporary improvement as lubricants can relieve the dragging effect for only a short time.  Lubricants are not designed to remove the sticky burnt oil residue which is the cause of stiction.  A short time after a lubricant has been added, the stiction symptoms return.  Treating stiction with a lubricant is like spraying cooking oil on a dirty frying pan.  It only masks the problem.  Actually, stiction’s negative impact to your diesel’s performance never left as it was simply masked by the lubricant.

Stiction can occur on your diesel’s injectors, o-rings, springs, piston and the turbocharger.  The most obvious symptom of stiction is a diagnosis of a failed injector.  Common symptoms of stiction occur well before your mechanic runs the diagnostics on your engine.  If you are experiencing slow starts or bucking and chugging, especially on cool mornings, stiction could be building up.  If your diesel hesitates to accelerate or has been losing power, then you could be experiencing stiction.  A steady and consistent drop in your MPG can also be an indicator of a stiction problem. To eliminate these symptoms, choose an additive specifically designed to remove stiction.

The “Failed” Injector Myth

It’s one of those experiences that diesel owners prefer to avoid.  Having to choose between an expensive repair or operating at impaired efficiency. A diagnosis of a “failed” injector can cost thousands of dollars in replacement costs. However, a closer look at the problem reveals an interesting insight.

Since the introduction of the 7.3 L Power Stroke in 1994, injectors have been relying on oil pressure to fire the piston via the HEUI fuel system.  International pioneered the idea of electronically controlled diesel engines in pickups, which became commonplace on GM and Cummins diesels.  Inside the injector, barely a thimble full of oil has the job of lubricating the piston, springs and o-rings. This oil is exposed to temperatures much higher than reported on your engine temp gauge. With enough time and heat, the oil breaks down and leaves a gummy residue on the inside of the injector. This “gumminess” can cause a slight hesitation in the piston or spring release which can cause a diagnosis computer to trigger a “failed injector” code. This gummy, sticky, friction is called stiction.

Frequently mechanics recommend replacing the injectors after the failure code is triggered. This is where the myth comes into play. While it is true that a replacement will solve the problem of an injector not performing correctly due to stiction, it is often unnecessary. The logic behind this replacement recommendation would be similar to replacing a leaky tire instead of plugging it, especially when there are plenty more miles to roll on that tire. Why replace an injector that is designed to go 1,000,000 miles? The elements of an injector are well crafted and can perform for the life of the engine. It is the stiction that is causing the failure, not the malfunctioning of the injector elements. Thus the “failed” injector myth.

While many drivers choose fuel additives to improve performance, the stiction that is causing an injector failure requires an oil additive. This is often counter-intuitive to diesel owners who consider the injector as part of the fuel system, not the oil system. Injectors require both systems to perform. A problem specific, high concentrate oil additive can remove the stiction and restore it to its original factory performance.

Common symptoms of stiction occur well before your mechanic runs the diagnostics on your engine. If you are experiencing slow starts or bucking and chugging, especially on cold mornings, stiction could be building up. If your diesel hesitates to accelerate or has been losing power, then you could be experiencing stiction. A steady and consistent drop in your MPG can also be an indicator of a stiction problem.

 Chris Gabrelcik is certified with STLE as a CLS and OMA.  He personally developed and tested a product designed to remove stiction called Hot Shot’s Secret Stiction Eliminator.­­

Does Hot Shot’s Secret Stiction Eliminator Really Work?

stiction-eliminator-300pxWe have been testing Hot Shot’s Secret Stiction Eliminator since 2004 and have found it to be 90% effective. Trucks having problems were hooked up to a diagnostic computer and tested. Computer analysis showed anywhere from 1 to 6 injectors needing replacement. A treatment of Hot Shot’s Secret Stiction Eliminator was added to the engine oil. The trucks were run only 100 miles and then the computer analysis was repeated. 86% of the time, the analysis showed all the injectors were back online. The owners noticed more power and a smoother running truck. The other 10% of the trucks showed improvement also, but not a complete cure. Most of the time, the diagnostic analysis showed that 4 injectors needed replacement before treatment. After Hot Shot Secret Stiction Eliminator was added to the engine, the analysis consistently showed only 1 injector needing replacement.